I dislike the idea of bundling upgrades, having them seperate allows for the most customization and variety of play. For example most usf players now get zooks and bars on their squads, instead of seeing some players get bars, some get just zooks etc. You just have to balance each upgrade, for example molos need a buff.
What. Making them both available promotes variety and customization. Most high level matches no one techs AT nades until needed and no one techs molotovs.
As for your USF example, that has nothing to do with the way upgrades are unlocked.